An operator interface assembly is provided that includes a frame having a first end configured to rotatably couple to a first lateral frame tube of an agricultural vehicle, and a second end configured to transition between a raised position adjacent to a second lateral frame tube of the agricultural vehicle and a lowered position beneath the second lateral frame tube via rotation of the frame about the first end. The operator interface assembly also includes a fluid inlet coupled to the frame, and configured to provide fluid to the agricultural vehicle. In addition, the operator interface assembly includes a valve coupled to the frame, and configured to control fluid flow from the fluid inlet to the agricultural vehicle. The fluid inlet and the valve are positioned adjacent to the second end of the frame, and directed laterally outward with respect to the agricultural vehicle.